Hunter 41DS Hydronic Heater Location

[Geoff E]

Hi all. I recently purchased a new boat (Hunter 41DS) last fall. Sometime during the very cold winter here on Vancouver Island while my boat was tied up in the marina, the red coolant from the hydronic heater unit leaked out and into the bilge. I am wondering what the best way to get a good look at this unit which is tucked in below the port stern cockpit locker and ahead of the the port stern propane locker. Has anybody had to replace or get at their hydronic units in the same location and if so, how did they do it. Thanks for any help you can give me.

 

[jviss]

Just wondering: this is the second time in the last month or so that someone has referred to what I think is their water heater as a hydronic heater. My understanding is that the term "hydronic heater" refers to a way of warming the air in a dwelling or boat by hot liquid, usually water, but also anti-freeze. The thing in your boat that heats potable water via engine coolant is usually called a water heater.

Is yours a water heater, or a cabin heater?

 

[Geoff E]

My hydronic heater for the boat operates as follows:
1. when the engine is not running, it can heat the water in the hot water tank. It circulates heated coolant through the heat exchanger in the hot water tank.
2. when the engine is not running, in addition to heating the water in the hot water tank, it also sends the hot liquid through to 4 separate coils with fans behind them and if the fans are turned on (4 separate switches) it blows hot air into the cabin.
3. when the engine is running there is a pull out switch by the electrical panel that has two positions. Pull out once for the engine to heat the water in the hot water tank and pull out to second position to heat water and the cabin.

These are the instructions I got from the previous owners. Still haven't had time to really check out all the solenoids and functions but I believe it to be correct as the previous owners were pretty good with instructions.

Thanks - Geoff

 

[jviss]

Thanks, Geoff, that clears it up for me!

Is the heater electric?

 

[dkinzer]

My Webasto hydronic heater is also located port side aft on my 41DS. If I crawl down into the starboard aft (swim platform) lazarette, I can squiggle my way over to the port side and see the entire unit except for the expansion tank which is in the port cockpit locker.

 

[Geoff E]

It's a diesel Hydronic Heater, Model D5WSC. I figured it out. I removed the stern propane locker and then crawled down inside to see the entire unit. It appears to be leaking the red coolant out of the side of the unit so I removed it to bring it home and inspect it. Either the o-rings need replacing or I've got a crack in it somewhere. Doesn't make sense though about the crack as I run antifreeze in the unit. I will get a seal kit for it or buy a couple stock o-rings and see if I can get it sealed up ok.

 

[Geoff E]

FYI, here's what I did. I removed the unit and took off the 2 tops. One of the tops is the water pump with an inlet and outlet and 2 o-rings that seat inside machined receptacles. I deduced from the baked on liquid red coolant that was on the top of the unit once the pump was removed that the leak was coming from above so I replaced the two old o-rings on the inlet and outlet and put it all back together. Reconnected all lines, filled the header, bled the coolant into the pump and then fired it up. Ran it for about 45 minutes and it was working great. Heated the hot water and the cabin very quickly. No leaks at the unit. I will keep an eye on it to make sure that was the problem. I believe the o-rings had gotten hard and then with the cold temperatures it started to leak. Thanks for your help.

 

[dkinzer]

[It heated] the hot water and the cabin very quickly.

My hydronic heater installation only heats the cabin - it's not connected to the water heater. I've been giving some thought to re-plumbing it so that it would heat water, too. Does your installation circulate engine coolant through the hydronic heater and the water heater, too or is there some valve set up so that either the engine or the hydronic heater can heat water?

 

[Geoff E]

The two systems are interconnected but there are solenoid valves that I just haven't found yet.

When the engine is not running, I turn on the hydronic heater, it heats and sends hot coolant through the engine, 4 separate coils with fans ( to heat the cabin) and the hot water tank. When the engine is running there is no need to turn on the hydronic heater. There is a pull switch beside the main electrical panel that is used to activate the solenoid valves. Pull out to first position for the engine to heat the hot water tank only and then second position to heat hot water tank and the 4 separate coils for heating the cabin. Hope this helps

 

[jviss]

I wish I had a heater like that. How much electrical power does it use?

 

[Geoff E]

Don't know but I don't think it's very much. I've only owned the boat for a few months and will start cruising for the season in another few weeks. I think the draw on that will be minimal. I've got 2 fridges (Nova Cool) and a deep freezer on board so that will be my main concern for power consumption. All new equipment this year so will have lots to play with. A couple solar panels mounted over the enclosure at the back should help immensely

 

[Hello Below]

I wish I had a heater like that. How much electrical power does it use?

I have the same furnace as Geoff E but with only 3 fan heaters vice the 4 he has fitted. The furnace draws about 4A in the high output mode (17, 000 btu/hr) and 2A in the low. Of course it cycles on and off under thermostat control. Each fan heater draws about 0.4A.
Edit: amended the heater fan current draw to make it numerically correct.

 

[Nachismo]

Can someone specify the make/model of this heater? Also, where is it vented? I have a 41ds & really want heat. Thanks

 

[dkinzer]

Can someone specify the make/model of this heater?

On my H41DS, it is a Webasto SG1577. It is mounted portside aft below the propane tanks and the exhaust through hull is on the port side near the stern, well above the water line. The expansion tank is in the port cockpit lazarette. In the attached photo, taken at the pre-purchase haulout, you can see the exhaust port just astern of the stripe.

 

[Nachismo]

THANKS!